Issue 6786 - Switch Safari 12+ users to content blocking API

safari/ext/content.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 (function()
 {
   // the safari object is missing in frames created from javascript: URLs.
   // So we have to fallback to the safari object from the parent frame.
   if (!("safari" in window))
     window.safari = window.parent.safari;
 
 
   /* Intialization */
 
-  var beforeLoadEvent = document.createEvent("Event");
-  beforeLoadEvent.initEvent("beforeload", false, true);
+  var applicatonVersion = navigator.userAgent.match(/Version\/([\d.]+)/)[1];
+  var majorApplicationVersion = parseInt(applicatonVersion.split(".")[0], 10);
 
-  // Decide if we should use the new content blocker API or not. (Note when the
-  // API is used Safari breaks the canLoad function, making it either throw an
-  // exception or return true when used.)
+  var beforeLoadEvent;
   var usingContentBlockerAPI = true;
-  try
+
+  // Safari 12 automatically disables extensions which use the old canLoad API,
+  // so avoid using the old APIs on Safari 12!
+  if (majorApplicationVersion < 12)
   {
-    if (safari.self.tab.canLoad(beforeLoadEvent,
-                                {category: "request",
-                                 payload: {type: "prefs.get",
-                                           key: "safariContentBlocker"}}) != true)
-      usingContentBlockerAPI = false;
-  }
-  catch (e)
-  {
+    beforeLoadEvent = document.createEvent("Event");
+    beforeLoadEvent.initEvent("beforeload", false, true);
+
+    // Decide if we should use the new content blocker API or not. (Note when the
+    // API is used Safari breaks the canLoad function, making it either throw an
+    // exception or return true when used.)
+    try

[Sebastian Noack, 2018/07/13 18:27:53]

It seems this kind of feature detection is obsolete now. Instead, we can only
rely on the Safari version now. In fact, there doesn't seem to be any scenario
where this would fail (on Safari 6-11).

[kzar, 2018/07/13 18:58:33]

I don't think this logic is redundant, it's how we figure out if the content
blocking is being used or not, which is still relevant for Safari < 12.

+    {
+      if (safari.self.tab.canLoad(beforeLoadEvent,
+                                  {category: "request",
+                                   payload: {type: "prefs.get",
+                                             key: "safariContentBlocker"}}) != true)
+        usingContentBlockerAPI = false;
+    }
+    catch (e)
+    {
+    }
   }
 
   var isTopLevel;
   var isPrerendered;
   var documentId;
   function notifyFrameLoading()
   {
     isTopLevel = window == window.top;
     isPrerendered = document.visibilityState == "prerender";
     documentId = Math.random().toString().substr(2);
 
     // Notify the background page that this frame is loading, generating
     // ourselves a random documentId while we're at it. That way the background
     // page can communicate with us reliably, despite limitations in Safari's
     // extension API.
     safari.self.tab.dispatchMessage("loading",  {
       url: window.location.href,
       referrer: document.referrer,
       isTopLevel: isTopLevel,
       isPrerendered: isPrerendered,
       documentId: documentId,
-      legacyAPISupported: "canLoad" in safari.self.tab &&
+      legacyAPISupported: majorApplicationVersion < 12 &&
+                          "canLoad" in safari.self.tab &&
                           "onbeforeload" in Element.prototype
     });
   }
 
   // We must notify the background page when this page is first loadeding (now)
   // but also when it is re-shown (if the user uses the back button to return to
   // this page in the future).
   notifyFrameLoading();
   window.addEventListener("pageshow", function(event)
   {
@@ skipping 99 matching lines @@
   /* Background page */
 
   ext.backgroundPage = {
     sendMessage: function(message, responseCallback)
     {
       messageProxy.sendMessage(message, responseCallback,
                                {documentId: documentId});
     },
     sendMessageSync: function(message)
     {
-      return safari.self.tab.canLoad(
-        beforeLoadEvent,
-        {
-          category: "request",
-          documentId: documentId,
-          payload: message
-        }
-      );
+      if (majorApplicationVersion < 12)
+      {
+        return safari.self.tab.canLoad(
+          beforeLoadEvent,
+          {
+            category: "request",
+            documentId: documentId,
+            payload: message
+          }
+        );
+      }
     }
   };
 
 
   /* Message processing */
 
   var messageProxy = new ext._MessageProxy(safari.self.tab);
 
   safari.self.addEventListener("message", function(event)
   {
@@ skipping 19 matching lines @@
   });
 
 
   /* Detecting extension reload/disable/uninstall (not supported on Safari) */
 
   ext.onExtensionUnloaded = {
     addListener: function() {},
     removeListener: function() {}
   };
 })();